On Tuesday, the same structure was dark and largely empty, after a massive and rapid inferno tore through it the previous evening.

Here’s a look at what the Gothic cathedral looked like before, and what it looks like now.

A combination picture shows views of Notre Dame Cathedral before and after a massive fire devastated large parts of the Gothic structure in Paris.

Charles Platiau/Reuters

A combination of two pictures made on April 16, 2019 shows people attending a mass at the Notre-Dame de Paris Cathedral in Paris on June 26, 2018.

Ludovic Marin/AFP via Getty Images

WATCH: Virtual tour of Notre Dame’s storied architecture

What was saved

Parisians crowded the centre of the city Monday, watching as firefighters worked to successfully save much of the building.

The fire spared its twin medieval belltowers, and a frantic rescue effort saved the monument’s “most precious treasures,” including the Crown of Thorns purportedly worn by Jesus.

Men work on a statue on a facade at Notre-Dame Cathedral after a massive fire.

Gonzalo Fuentes/Reuters

The iconic stained glass Rose windows appeared to have survived — a stroke of luck given the difficulty of reproducing such ancient glass.

A view of the stained-glass windows inside Notre-Dame de Paris in the aftermath of a fire.

Christophe Petit Tesson/Reuters

Smoke rises around the altar in front of the cross inside the Notre Dame Cathedral as a fire continues to burn in Paris.

Philippe Wojazer/Reuters

Interior view of Notre-Dame de Paris in the aftermath of a fire that devastated the cathedral, during the visit of French Interior Minister Christophe Castaner (not pictured) in Paris, France, April 16, 2019.

Christophe Petit Tesson/Reuters

The Roman Catholic cathedral’s famous 18th-century organ that boasts more than 8,000 pipes was also reportedly saved, after a plan to safeguard the masterpieces and relics was quickly put into action after the fire broke out Monday.

Sixteen copper statues of saints, which usually adorn the spire of Notre Dame, had a “miraculous” escape from the fire, after being removed last week for restoration work.

Consultant Patrick Palem checks statues that were removed from the spire of Paris’ Notre-Dame Cathedral in a workshop at the Socra company for restoration work in Marsac-sur-L’Isle, France.

Regis Duvignau/Reuters

Consultant Patrick Palem checks statues that were removed from the spire of Paris’ Notre-Dame Cathedral in a workshop.

Just a day after the fire, more than 750 million euros (US$845 million) had been pledged, including 500 million from the three billionaire families that own France’s giant luxury goods empires: Kering, LVMH and L’Oreal.

But some say repairs are much more complicated and will take longer.

WATCH: Notre Dame Cathedral joins other icons destroyed by fire

Peter Fuessenich, who oversees reconstruction for the Gothic cathedral in Cologne, Germany, said it could take decades to repair Notre Dame.

Cologne Cathedral was heavily damaged during World War II and work to repair it is still ongoing more than 70 years later.